How green is your ride?: 'Environmentally friendly' means different things to different people

By
J.P. Vettraino

Apr 21, 2008

Some car folk have asserted, with a hint of sincerity, that the greenest car ever sold is the Rolls-Royce Silver Shadow. Of 38,000 Silver Shadow variants built between 1965 and 1980, some 90 percent are still registered and roadworthy.

By this measure of greenness, Aston Martins and Ferraris probably run a close second, though it's a safe bet that more of those have been wrecked. As counterpoint to these enduring automobiles, the National Automobile Dealers Association reports that 12 million cars and trucks were scrapped in the United States in 2006. "Scrapped" in this context covers a range of possibilities, from systematically recycled to submerged in country ponds.

In a thoughtful debate on environmental impact, few will hold fast to the notion that a Silver Shadow is the greenest car. But the point is taken. With attention focused on sexy propulsion sources, considerations such as manufacturing, duty cycle and disposal get lost in the roar. Does anyone really know what the most ecologically friendly car is?

Science can only guide us, and often the science gets buried under hype from all corners with something to sell.

"There's been a sincere effort to give consumers a rationale for comparing the eco-performance of vehicles," says Shruti Vaidyanathan, principal vehicle analyst at the American Council for an Energy Efficient Economy (ACEEE). "There's also a lot of hard sell that isn't based on good policy or science, and there are gray areas in measuring eco-performance. The ends of the life cycle are among the biggest."

Gasoline-electric hybrids--particularly the Toyota Prius--have quickly become poster children for various environmental advocates. But there's plenty of evidence that hybrids aren't the greenest vehicles to build. One European think tank recently suggested that hybrids and their marketing schemes are actually impediments to genuinely sustainable green automotive technologies.

For 11 years, ACEEE has published its Green Book, which ranks vehicles according to a green score, tabulated using "a singular measure that incorporates fuel economy, health-related pollution impacts, global-warming emissions" and other environmental factors. The greenest vehicle for 2008? It isn't the Prius but a Honda Civic, and it's not the Civic Hybrid, either. For the fifth consecutive year, ACEEE's greenest car is the Civic GX, powered by compressed natural gas (CNG).

That's partly because CNG is one of the simplest of all hydrocarbons, leaving less CO2 for each unit of heat released during combustion. So the Civic GX can burn considerably more fuel (by energy content) than a Prius and still generate less of the greenhouse gas. Again, however, operating emissions are only part of the equation. As an example, consider hydrogen.

In the green-fuel scheme, there's no obvious drawback to hydrogen, and Honda has begun leasing its FCX Clarity hydrogen-fuel-cell sedan to carefully selected customers in California. Yet the zero-emissions FCX Clarity will absolutely alter nature's ecological balance. Exactly how much isn't clear, because cradle-to-grave analysis remains the fuzziest component of green-car evaluation. Today's fuel cells require platinum, which means mining a rare metal and then finding some means of recycling it.

Hype about benefits, as usual, is abundant. No one blows a trumpet for the downsides of their proposed alternative automobiles.

In the spring of 2007, it was widely reported that nickel for the nickel-metal-hydride batteries in the Prius is mined and smelted near Sudbury, Ontario. Sudbury happens to be known as one of industry's great environmental disasters. For decades, sulfur dioxide released in the smelting process killed all but the most acid-tolerant vegetation in the surrounding countryside, to the point where the barren, moonlike landscape was used as a training site for Apollo-program astronauts. Prius bashers seized the news as an indication of the car's true color.

Blaming the Prius for Sudbury's eco-disaster is like blaming the Exxon Valdez incident on a brewery. Damage in the region resulted from a century of nickel mining and smelting, and it had largely been reversed before the first Prius was built. Picking on the Prius also assumes that other automobiles don't contain nickel, and they all do. If Sudbury has relevance to the greenness of the Prius, it rests largely on highlighting cradle-to-grave impact.

ACEEE weighs life-cycle impact in its green score, but the group's methodology pointedly notes: "Standardized, model-specific data on the environmental damage of vehicle manufacturing are not available." Nor are there "sufficient data to estimate vehicle-disposal and scrappage impacts." Ultimately, the green score weighs manufacturing and recycling based on mass. The heavier the car, the bigger the impact.

Still, it seems fairly obvious that hybrid and other green-tech automotive production is more complicated, energy-intensive and potentially disruptive to the environment. Toyota allows that its hybrid production requires more energy than conventional production, particularly in materials processing, but counters that extra energy used in the cradle is dwarfed by energy saved during the hybrid's operational life.

The standard life-cycle-impact assessment applies a 15/80/5 formula: 15 percent manufacture, 80 percent operation, 5 percent disposal. The roots of 15/80/5 appear to be academic intuition or a research hypothesis established in the 1980s as a starting point. In the mid-1990s, Volvo undertook what it expected to be a definitive analysis of energy used to build its cars, from the extraction of raw material through various levels of suppliers to final assembly. When the scope and complexity of making any reliable assessment became clear, the company gave up. The 15/80/5 model hasn't evolved much since, though recent studies have challenged its validity.

In 2005, CNW Research (www.cnwmr. com) published the first of its controversial "Dust to Dust" Automotive Energy Reports, which purport to measure "the energy necessary to plan, build, sell, drive and dispose of a vehicle from initial concept to scrappage." This small Oregon-based company is typically retained by carmakers for market research, as are more familiar firms such as J.D. Power, though CNW says that "Dust to Dust" is not a funded study. The lengthy report seems to be based on data available in libraries or on the Internet, as well as factory and facility tours. It concludes that the 15/80/5 formula is way out of whack. In some instances, most energy consumption occurs before the vehicle reaches a consumer's driveway.

"Dust to Dust" ultimately converts a vehicle's energy use into "cost per lifetime mile." By CNW's assessment, the greenest vehicle available in 2007 was Toyota's Scion xB, followed by the Jeep Wrangler. The Prius ranked 74th, below Land Rover's Range Rover and the Aston Martin DB9.

CNW's methodology and conclusions have been challenged by many, most prominently by environmental groups. Again, though, there's a point to be taken: There's more to green than mpg.

Subaru's assembly line in Indiana was the first automobile factory certified as a zero-landfill plant, and it's widely accepted as one of the cleanest factories in the world. So, how much does it matter that the conventional Tribeca SUV built there suffers in the ACEEE's green score because its engine is certified at a slightly higher emissions level than some others? Ford's F-150 pickup, often cast as a dinosaur of old tech, is built at Ford's new Rouge plant, with its sedum-covered roof to filter rain runoff and convert CO2 through photosynthesis and solar panels that heat the water and provide excess energy for other applications. Estimates rank the F-150's supply, assembly and customer-transportation costs among the lowest in the auto industry and those of the Prius among the highest.

If 15/80/5 was ever accurate, the ratio is sure to change as vehicle operation generally gets cleaner, and the ends will gain weight. We've made leaps in propulsion technology, but we've moved less in other areas.

When do we get a properly designed, expansive and adequately funded cradle-to-grave study of the automobile's environmental impact, untainted by the biases of either automakers or environmentalists? If we're sincere in the desire to make our beloved car as ecologically friendly as it can be, we need one. And, as always, we need perspective and common sense.

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